


Survival

by hunters_of_221B_from_Gallifrey



Category: Supernatural
Genre: Biosuit, Dean likes it up the butt apparently, Dubious Consent, I NEEDED THIS, I'm so sorry, M/M, Other, Symbiotic Relationship, Tentacle Sex, Tentacles
Language: English
Status: In-Progress
Published: 2016-04-22
Updated: 2017-01-03
Packaged: 2018-06-03 18:13:13
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 5,202
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6621067
Author URL: https://archiveofourown.org/users/hunters_of_221B_from_Gallifrey/pseuds/hunters_of_221B_from_Gallifrey
Summary: <blockquote class="userstuff">
              <p>Dean finds something a little more than he bargained for in a warehouse on a hunt. And it wants something from him.</p>
            </blockquote>





	1. Chapter 1

"I don't get why you think we need to be here Sammy. Can't we get someone else on this? We have tons to do back at the bunker." Dean whined as he drove into the town. He was pretty sure his car was bigger than this minuscule place. Sam sighed and put his phone down on his lap. 

"Because people are dying, it's not too far, and we need to take a break, you more than anyone." Sam reminded him. "Listen, you are running yourself thin with this whole thing with Amara and Cas and Lucifer. We could use some time away from the bunker." Sam looked out the window at the town. "And from what I can tell, it looks like just a djinn case. I'll check out the bodies, you check out some warehoused around here, see if it's there. The bodies were found in different warehouses."

"Alright. Here you go." Dean pulled over to the curb at the morgue, and he let Sam out, then he headed towards the first warehouse on the list. He checked out all the ones on the list, keeping his silver knife on him as he searched.

Three warehouses in, he noticed something...different about it. It was darker, both physically and the way it felt. Dean noticed some sort of wetness on the floor too, sticking his shoes to the floor. "What the fuck is this?" Dean muttered to himself, raising his foot to look at the goo covering his boots. That was when he noticed something peeking at him from around a corner. "Hey, come out here and face me like the fucker you are!" Dean shouted, wielding his knife at the creature.

Something caught his eye, darting out of his line of sight, making him turn quickly, away from the thing he had seen first.

That was his first mistake.

Something lashed around his ankle, pulling him down face first in the goo on the ground. Dean struggled against it, stabbing his knife into the thing on his ankle as much as he could before another something grabbed his wrist and pulled it away, twisting his arm until he had to let go of the knife. "Stop it! Let me go!" Dean snarled, feeling how...slimey the thing on his limbs were. 

Another two things reached out from the darkness to grab his other ankle and wrist, leaving him spread out in the air as they lifted him from the ground. He struggled hard, yanking his arms and kicking his legs as much as he could. That's when he saw what the things were that had his limbs tight in their grasp. Were those...fucking  _tentacles_?

The small light coming in from the darkened windows was just enough to see what was holding on him, and the approaching tentacles towards him. "Oh fuck no." Dean snapped when he saw the tentacles starting to skirt over his clothes form, pulling on his jacket and the hem of his pants. Another one slithered down his arm and started pushing on Dean's lips. Dean turned his head against the tentacle, not letting it into his mouth. Until another tentacle slipped into his shirt and somehow just sucked on his nipples, making him gasp in shock. The limb thrust into Dean's mouth, cutting his air off in a sudden push. Dean choked as he felt the tentacle press down past his molars and into his throat. 

Dean tried to bite down on the limb, but it was too mushy, it was like biting down on jelly. It just sprung right back, then it wedged itself between his teeth, so he could bite down and his jaw was forced to stay wide open around it. 

Other tentacles kept exploring his body, finding offense in the clothes Dean had on. Because in mere minutes, the tentacles had ripped them to shreds, leaving Dean completely nude in the air. Dean yelled against the tentacle in his mouth, desperately trying to get away. He had seen enough anime hentai to know where this was going. Those little animated girls always ended up completely fucked over. And he wasn't too far from that now.

A thin tentacle slide down his back towards his ass, but instead of immediately going inside him, it wrapped around one of his ass cheeks, squeezing it hard, then another went for the other one. He felt the tentacles pull his ass apart, showing his hole to whatever the creature was, giving it full access to him. Dean widened his eyes when he felt it, squirming more until he felt a pinch in the back of his neck.

 _Struggle not, human. I will not damage you permanently. I have created a temporal link between us, so you may speak in your mind. I will hear you._ Something deep and ancient spoke in his head, and Dean was silent for a moment. 

"What are you? And if you're not gonna hurt me, why did you leave all those dead bodies?" Dean snapped in his head. He then heard a light chuckle.

 _They weren't compatible with me. I have not found a human that could take me and support me. But you? You were meant to hold something greater than yourself. You are a Vessel._  It purred into his head.

"A Vessel? Uh, yeah for an angel though. Not you. And I've never had an angel inside me. And you won't be inside me either!" Dean shouted back, feeling some more of those small tentacles caress his dick. Dean moaned, though he didn't want to.

 _It is perfect. You are untouched in all the ways that matter. I wish to become one with you. I am called a word that you could not comprehend, but you may call me Synosus. I am older than you could believe, and in all these years, I have only found beings to keep me sustained. However with you, I could live with you, and die with you. I would become one with you, live with you, provide for you. I would never hurt another human, not even you. You would be my Vessel, and I would sustain you for a very long time, keep you healthy, keep you happy. Only when you were ready would I let us die together._ Synosus explained. Dean was shocked. Was it...asking his permission? 

"I-If you are just trying to live with me, then why am I naked?" Dean retorted, trying not to react to the stimulus that was getting him hard. 

_Because I would live within you, on your skin, inside your body. I would become part of you both physically and spiritually. I will give you pleasure when you desire, I will give you comfort when you need it. I will be all you need._

Dean thought for a long time about the offer that Synosus had made him. If he chose yes, then he would live the rest of his life with a monster attached to his body. He had no idea what would happen if he chose no. But then again, if he chose no, more people would die trying to sustain this thing. Synosus didn't seem...bad. He just wanted someone to live with. 

"If I say yes...I would still control myself, right? I would still be in charge of my own body?" Dean asked.

_Of course. I wouldn't dare take your free will away, Dean Winchester. It will be as if you are wearing something. We will be symbiotic, I will not be parasitic._

Dean looked into the darkness, and he gave a small nod around the tentacle in his mouth. "Then yes."

With that word, it was as if he had let a storm loose. The tentacles that had held his ass cheeks apart suddenly squeezed again, while another oozed something cold and slick onto his hole while the thin limbs around his dick wrapped around his cock and balls, squeezing and pulling occasionally.

Dean whined loudly around the tentacle in his mouth when he felt the cold stuff on his ass, wriggling in the hold of the tentacles. “How…how are you gonna get inside me?” Dean asked, knowing that the link was still intact, since he could feel the creature’s pleasure in his head. He also had a feeling he knew how this was going to go, but he asked anyway because he just needed to know explicitly what would happen to him before Synosus would be done.

_Worry not, my Dean. I need to enter your orifices. It may feel strange, but I have made sure you will feel no pain while it happens. Only pleasure._

Dean suddenly became worried. Orifices? What the fuck did that mean? What kind of orifices?!

Dean’s answer came when a tentacle eased into his hole, making him cry out with sudden pleasure. It was weird, because it felt massive, like he was being split open on the tentacle, but it didn’t hurt. He vaguely thought it might be because of what Synosus put on his ass before, or maybe he was just magic.

Dean moaned as the tentacle just kept going, traveling up his ass until he could feel it poke the skin at his belly. He looked down, seeing the skin of his stomach bulge obscenely around the intrusion. Dean let out an honest whimper when he saw it, but his fear was soon diverted when a very tiny tentacle decided to plunge into the slit of his cock. He jerked in the grip of the many tentacles, his eyes wide as he tried to get it out. Oh hell no. Orifices meant everything!? He seriously hoped those were the only ones that Synosus meant.

He bucked his hips forward against the tentacle in his dick, then back against the one in his ass, building up heat in his belly from an approaching storm of pleasure. “Please…I-I gotta come, take the thing out of my dick!” Dean choked out in his head, pleading for some sort of release.

_I cannot take it out, not until I am done. But I promise release will come soon._

Dean made a sound of distress around the tentacle in his mouth, which seemed to be getting deeper in his throat as well, working down his esophagus. He choked, but a sudden spurt of liquid in his mouth made his gag reflex stop. Another tentacle started to play with his ear, dipping in and seeing if that was another place it could enter. Dean was about to say something against it when that tentacle and another suddenly plunged into his ears.

Dean screamed, mostly in terror, since he didn’t feel any pain, but he also couldn’t hear anything now. “Get these out of my head!!! Stop!!!” Dean shouted, tears starting to run down his cheeks as pure fear made him close to crying. A gentle little tentacle swept across his cheeks and wiped away the salt water.

_Be still, Dean. I am nearly finished. When I am done, you will understand._

Dean didn’t want to understand, he wanted to go home. But he said no now, then this would happen to someone else, it would happen to more people and they would die because of it. Dean was ending a cycle of pain and loneness, and he tried to remind himself that.

It became hard when two last tentacles decided to plug up his nose. Dean tried to inhale suddenly, but there was no way to breathe, with the tentacle in his mouth, and the other two blocking his nose. He jerked violently, trying to breathe desperately.

“You lied to me! You’re killing me!!” Dean bellowed in his mind, though it was beginning to get fuzzy.

Just as he was about to hear a response, a sudden contraction in his stomach and ass made him scream, and he orgasmed harder than he ever had before, his senses whiting out as he passed out in the hold of the creature, and he knew he wouldn’t wake up.

* * *

 

Dean did wake up, though, and when he did, there was nothing in sight. He was dressed, clean, and very much alive. Dean frowned as he woke up, looking around the warehouse and noticing that even the slime from before was gone. It looked like a normal warehouse, dirty, but nothing out of the ordinary.

Dean stood up, groaning at his sore muscles. He must have been dreaming. And he…had to have passed out when he got there. He muttered a small promise to never drink and hunt again and headed towards his car.

_Hello Dean._

That voice whispered it into his head, and Dean spun around, not seeing the source of the voice.

“What?! Who said that?!” Dean asked, and that was when his _clothes started moving_.

_Oh Dean, have you forgotten about me so quickly? I told you, it was all pleasure, not pain. I apologize about cutting off your breathing, but you had to trust me in order for it to work._

“Oh…it’s you. Uh… why are you in my clothes?” Dean asked, trying to find where he was in the soft material.

_I am your clothes. I told you, I am very malleable, and I can be anything you want, a weapon, a shield, even clothes. Also, I am willing to please you again like I did before. Anything you want, I will do._

Dean thought for a moment, then he gave a little smile. “Can you make a silver knife?” Dean asked.

He watched as his skin moved towards his hand. It felt like something crawling on him, but it didn’t hurt. The extra skin molded itself into the shape of knife, then hardened into silver. Dean touched it and was surprised by the fact that it was perfect. “Wow. Okay, that’s really cool. What about food and that kind of stuff?”

_Unfortunately, since we live as one, I cannot provide you food. But I have no barriers to what we must eat._

Dean shrugged. That was fine, he could deal with continuing to eat. He always had, and he probably would have continued even if he didn’t have to eat. “Okay then, let’s go back to Sammy.” Synosus buzzed in his mind for a moment, taking in the idea of ‘Sammy’, then he felt it get happy.

_Siblings! I have never had siblings, but I am glad to meet Sam._

“Oh…uh, we should probably keep this on the down low for now, since Sammy probably won’t be a fan, okay?” Dean said, rubbing the back of his neck. “And…do you think you could maybe use those tentacles you started with on me in the future? Cause…when I wasn’t terrified of dying, they felt really good.” Dean almost felt Synosus smile.

_It will be my pleasure._


	2. Castiel

**Summary for the Chapter:**

> Dean's new life has been going swimmingly so far with Synosus, but someone is a little too curious for his own good.

Dean's life continued relatively normally.

It saved him a lot of money on clothes and weapons to have them within his skin, and he didn't have to worry about gun shots or stab wounds since Synosus could take care of them easily, or prevent them in the first place by making body armor that was stronger than Kevlar. Dean even tried it out once, hardening the skin on his hand and trying to cut into it with one of his knives, but the only thing he felt was a little touch from the razor point. 

Of course Sam couldn't know though. Dean still had to buy things to make everything seem normal. He didn't want to all the sudden just start going without clothes but still have things to wear or things to wield in a fight. 

His favorite thing, however, was probably his... relationship with Synosus. Sure the thing was a centuries old creature with a real name he couldn't even hear let alone pronounce: but that didn't mean they couldn't have some fun. Dean loved spending his 'alone time' with Synosus, using his abilities to do everything he wanted at once. He could touch himself everywhere and at the same time he could just let himself be touched. It was perfection.

It was like that for a few months, Dean being normal and Sam not seeing what had changed despite that Dean looked healthier than ever. Then, everything changed when Castiel started looking at him strangely. 

It was subtle at first, nothing that Dean could really put his finger on, but Cas would just stare at him. He didn't notice until Synosus actually said something. 

_ I have noticed that the angel looks at us more than normal.  _

**What? Has he been?**

Dean turned around and he saw Cas turn his head at the same time, making him begin to simmer with curiosity. Why had he been looking at him enough that Synosus would notice? 

_ Dearest,  _ a pet name Synosus had begun to call Dean,  _ I believe we need to confront Cas about it. Also about how we feel. _ Everything in Dean's head was now multiplied by two. He wasn't just a  _ he _ , he was a  _ they _ . And he knew that  _ they _ both had a bit of a crush on Cas. Dean's was old, a couple years now, but Synosus? He had loved Cas since almost day one. He was so interested in the angel, how they could share common experiences, how they could enjoy one another's company... yup, they loved Cas a lot, but they were too chicken to do anything about it.

**I'm not going to admit it. You know he'd just shoot us down. Especially when he finds out about us.** Dean said, feeling ashamed of Synosus again. Since Dean was not facing Cas at the moment and Sam was gone, Dean felt a slither under his skin that caressed his face gently. He sighed and touched it before it sank back into his skin.  **I know you don't like it when I complain about us, but you know that he won't like it.** Dean insisted.

_ I do know that, but we can convince him to see our way.  _

Dean looked at Castiel, and he got up and walked over to him, Synosus somewhat helping him keep going towards Cas. 

“Hey Cas. Uh, can we talk? I’ve been meaning to talk to you about this for awhile now.” He said, and Cas looked at Dean with a furrowed brow. 

“Of course, Dean. You know I enjoy our talks.” Cas assured him as he stood up and followed him into one of the rooms off the side where Dean closed the door behind him. 

“I don’t know if you’ve noticed the past few months that I’ve been...different.” Dean said, his voice getting more confident as he went. They could do this. Together. Cas’ face shifted into something that seemed to be foreign to his face: confusion. It was a combination of curiosity, wonder, and a slight air of anger. 

“Yes, I have noticed. You look...healthy.” He noted first, though he quickly continued before Dean could butt in. “However, when you aren’t looking, there are things that... _ move _ on you. Unnaturally. You don’t seem to even realize it. Also, you are now much more likely to get lost in your thoughts. While normally that wouldn’t be a bad thing...I can hear two voices in your head, Dean.”

“You’ve been listening to my head?!” Dean snapped, anger from them immediately rising. “Cas, come on I’ve told you time and time again that you can’t just fucking spy on people’s heads like that-” Dean suddenly stops when Cas shakes his head rapidly.

“No, no! Dean, you know I would never. But your mind...I could sense it without even doing such a thing. It’s an ancient power, perhaps even older than I. Could I try and figure out what it is so I can rid your body of it?” Castiel stepped forward with a glowing hand at the ready.

Dean stepped away from it, his eyes wide. “No! Cas, stop! It’s not bad! We’re fine!” Dean cursed under his breath when he said the word ‘we’.  **Fuck, Syn I don’t think we can avoid this.**

_ I agree dearest. I believe I should tell Castiel this. I don’t want him to think us freaks. _ Synosus came forward and took over Dean’s body and mind, which Dean gave willingly. They had been practicing this for when they would tell Sam, but this would work. Dean straightened his back and his eyes changed, a soft smile coming to his face. His eyes were now a bright golden hue, shining with life that was not Dean’s.

“Hello Castiel. As you can tell, Dean is trying to tell you something but he is not doing so well. My name is Synosus. Dean and I now share this body and are symbiotic.” Synosus explained, but Castiel drew his angel blade. 

“Give me one reason why I should listen to you. You’ve taken Dean’s body!”

“Actually, he gave it willingly. We are both a single organism now. We provide for each other.” He raised his hand and the skin molded to form an angel blade as well. “I am about a century older than the first angel, and your father made me in order to help the creatures he would eventually make called humans. They were too fragile by themselves, so my species was created to help humans become more adapted to the elements. Without us, humans would have died off before they could have even figured out how to wipe their own asses.” Synosus gave a slight smirk. “I’m afraid Dean is beginning to rub off on me. But you can read our mind. You can tell I am telling the truth, and believe me. I am only here to help Dean. Since we became one, he has not once had alcohol, nor has he done anything that would harm him. We can craft weapons with skin, as well as clothing and other needs.” Synosus explained as Castiel sat down on the bed, putting his head in his hands. 

“What you are saying is that Dean is now not a single entity? And why? Why him?”

“Because Dean was originally meant for an Archangel. Other humans cannot take me without dying, but Dean thrives with me. We are meant to be one.” Castiel shook his head and stood again, his hand steady despite his obvious discomfort.

“Why didn’t you take a human when my Father first made humans?” Castiel inquired. He was beginning to calm down, but he didn’t like it still. 

“I was unable to find someone. I was much like you and the Winchesters. I questioned my purpose for a very long time, but then I realized that I had to do what God created me for. However by that time, the humans had long worked my kind out of their system. Only those with the bloodline that had my species could take me. Seeing as the Winchesters are directly related to Cain and Abel, those two were some of the first that hosted us.” Synosus explained, then his head tilted. “Dean would like to speak to you now.” Castiel stood straighter, putting his angel blade away so it was no longer threatening them. 

“Yes, of course.”

“Cas.” Dean spoke, and his voice and eyes immediately changed. He relaxed, his eyes went back to their vibrant green color, and he sounded like himself once more. “I’m sorry I didn’t tell you sooner, but honestly….I didn’t know how to. I didn’t want you to look at me differently. I’m still Dean, and I always will be. But now i just have...a little extra baggage.” Dean gave a crooked smile, something that was almost trademarked to Dean alone. Castiel relaxed even more, looking over Dean much more thoroughly.

“Now that you told me everything, I can see his presence within you. But he was right. It is not parasitic. You are quite healthy. Not a single hint of your previous heart issues nor your liver problems.” Castiel squinted his eyes at Dean. “Though I am not particularly happy that you kept such a thing from me for so long, I would never judge you for such a thing, Dean. You are your own man, and you can tell if something is wrong. Remember, if anything goes wrong with the creature-”

“Synosus.”

“With….Synosus, I will find a way to get him out of your body and kill him.” Castiel swore with a scowl. Dean could feel his skin shiver, and he wasn’t sure if it was the look that Castiel gave him or Synosus agreeing. 

_ Dearest, I do believe there is one more thing we need to tell Castiel. There is no better time than the present.  _

**Oh come on. Now? No way, I am not telling him now. How would I even do it? “Hey Cas, me and the thing in my head are in love with you. Let’s do it”?**

_ Well if you wish to be so blunt about it. Wait, that was sarcasm, wasn’t it? If you wish I could tell him. _

**No, no… I just really don’t want to.**

_ If you do not, then you will never-- He is reading our mind. _ Dean’s gaze snapped up to Castiel, his eyes wide in shock. 

“I-I apologize Dean. I didn’t….I asked a question and when you didn’t answer I wanted to make sure you were alright within your mind. I didn’t mean to intrude on a… conversation.” He said. A strange sight began to unfold before Dean: Castiel got nervous. His cheeks started to get flushed and his voice got stuttery, which made Dean think he knew exactly what he just said. “I didn’t hear much, but I am sorry.”

“Cas, we love you.” Dean blurted out suddenly, deciding that he just needed to do it. 

“What?”

“Cas… since the moment you burst through those barn doors, I knew that there was something different about you. I didn’t know it then but...you were something so….ethereal that I couldn’t even understand why you were on the ground with us. I think it was the night you saved me from that horrible future and you told me we had an appointment...that was the night I fell for you. And then you proceeded to fall for us. For me. I really….I love you Cas, more than I thought I could love anyone. And I guess it took Synosus to make me say that. And through me, Synosus has fallen for you too. He loves how strong and brave you are, how...well, how freaking hot you can be sometimes. We both love it. So...if you’ll have us, I think that would be freaking fantastic.” Dean took a deep breath once his feelings had been put out there. He felt...empty. He had been holding onto those feelings for so long that he didn’t know what to do now that they were out in the open.

Castiel looked like someone had punched him in the stomach. His mouth was slightly open and he was bent over a bit, like it was hard to breath. Castiel’s face was as red as blood, though only recent it was as though the blood had left his face. He was breathing funny, little short inhales and long exhales, and he wasn’t facing Dean. He was looking down at the ground.

“Uh...Cas?” Dean was worried at this point. He had never seen the angel so….human. Even when he had been human. “Are you--”

“I need a moment. Please.” He held up a finger. Dean nodded and stayed silent.

The room felt like it was closing in on Dean, the air growing thick in his throat as he tried to suck in another deep breath. Jesus fuck, what if Cas said he didn’t reciprocate the feelings? What the hell would he do then? Dean could never look at Cas the same way. Not after that confession. And if Sam found out? He wasn’t sure if Sam would ever let him live it down. Dean was about to go into a full blown panic attack when the soothing sound of Synosus’ voice filled his head.

_ You are panicking, dearest. Shhh, do not be afraid. We will take whatever Castiel says to us and we will understand and appreciate his answer. However, I do not think he will say he does not feel similarly. He has done too much for you to be indifferent. _

**He doesn’t have to be indifferent. He can like me, but not...like like me. Plus he never thought of you being in the picture!**

_ I do not believe this would be my fault. Castiel has already said he would support you with anything. If he truly loves you, perhaps he could love me too. _

**You sound like a school-girl with a crush.**

_ Oh trust me, dearest. It is much worse in your dreams at night. _

Dean’s retort to Synosus was cut short by Castiel’s sudden movement. He looked up and his eyes were determined. Castiel had decided something and was sure of it.

“Before I speak, you must allow me to say my whole piece with no interruption, do you understand?” Castiel spoke firmly. Dean nodded, and Castiel continued, “When I was first given my assignment of saving Dean Winchester from Hell, I believed that it would be just another charge. I couldn’t tell you how many I had in my long lifetime before the simple task of rescuing someone from Hell. And they had all ended the same. I had done my part, they lived, then they died. I was sent on to my next task. I never cared. I had no reason to. They were humans. Weak, pathetic humans who had no meaning beyond a blip on my radar. But then, the moment that I saw your soul in Hell…I knew something would change. It was a brilliant thing to behold, like looking at a star on a dark night. I touched your soul and in a millisecond, every memory, feeling, idea, emotion….everything that made you….you, I could feel it. It changed me. I tried to pretend that it didn’t, but it never worked. I could never identify what it meant to me, what you were to me. I think I realized what it was in Purgatory. I remember an angel once telling me that love was a burden, that it hurt more than it felt good. Also that it meant you would hurt forever to spare that person a second of agony. When you found me there...I knew that I would do anything to get you home, and I would stay to keep you safe. But now...with the label on it. I believe that...yes. I do love you Dean Winchester. And Synosus...I am flattered. I believe I could learn to love you as well.” Castiel gave a warm smile, and Dean threw his arms around him with a joyous laugh.

“Oh Cas, thank you. I knew… well I mean I didn’t know, but I knew that you felt that way too!” Dean grinned, giddy from the idea that Cas actually loved him too. 

Things were turning out nicely.

**Notes for the Chapter:**

> There was an overwhelming number of people who wanted this to continue. First I give you some fluff to pass you by, then I will give another chapter with some nice smut as well as Sam finding out about Synosus. Hope you liked it and please comment on any ideas, suggestions or just comments you might have for this story. Thank you all!


End file.
